A high-toughness and low-swelling ion-conducting hydrogel, a preparation method and applications thereof

Abstract

The application discloses a kind of high tough low swelling ion conductive hydrogel and preparation method and application thereof, belong to high molecular hydrogel technical field, including, acrylic acid, acrylamide, phytic acid, sodium carboxymethyl cellulose is dissolved in deionized water, mixed uniformly, obtain precursor solution;Bubble in precursor solution is removed, and the precursor solution of removing bubble is prepared;Initiator, crosslinking agent are added to the precursor solution of removing bubble, stir to completely dissolve, obtain pre-polymer liquid;Pre-polymer liquid is polymerized under preset condition by free radical, obtain high tough low swelling ion conductive hydrogel.The application is developed multifunctional ion conductive hydrogel by the synergistic effect of phytic acid and carboxymethyl cellulose, the gel has excellent mechanical properties, can also be realized in water and artificial seawater Low swelling, also have good conductivity.Preparation method is simple, operation is controllable, easy to industrial production.

Description

Technical Field

[0001] This invention belongs to the field of polymer hydrogel technology, specifically relating to a high-strength, tough, low-swelling ion-conducting hydrogel, its preparation method, and its applications. Background Technology

[0002] Ion-conducting hydrogels have shown significant potential in the field of flexible bioelectronics due to their excellent flexibility, conductivity, and mechanical compatibility with biological tissues; among them, flexible wearable sensors have become a research focus because they can monitor physiological signals and motion in real time. Ion-conducting hydrogels possess unique tensile-sensitive properties, with their resistance changing according to applied tensile strain, making them ideal materials for constructing flexible wearable sensors.

[0003] However, despite the development of various flexible wearable strain sensors based on ion-conductive hydrogels, while these materials exhibit good sensitivity in signal detection, limitations remain, including insufficient mechanical strength, narrow operating range, and low toughness. Furthermore, repeated deformation during use significantly impairs their signal detection capabilities; and the high swelling properties of ion-conductive hydrogels are also a major constraint on their development.

[0004] Since ion-conducting hydrogels are typically made of hydrophilic materials far from swelling equilibrium, most of them tend to swell in aqueous solutions during their application. Although the three-dimensional cross-linked structure usually prevents the hydrogel network from disintegrating during swelling, the volume expansion of the hydrogel can significantly reduce its mechanical and electrical properties, severely limiting its applications.

[0005] Currently, achieving high mechanical properties and low swelling has become a key requirement for ion-conductive hydrogels. Therefore, an ideal ion-conductive hydrogel for flexible wearable sensors should not only have good sensitivity, but also high strength and toughness, fatigue resistance, low swelling, and a wide working range, and should also maintain good mechanical and electrical properties after swelling. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0007] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0008] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a high-strength, tough, and low-swelling ion-conducting hydrogel.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a high-strength, tough, low-swelling ion-conducting hydrogel, comprising,

[0010] Acrylic acid, acrylamide, phytic acid, and sodium carboxymethyl cellulose were dissolved in deionized water and mixed thoroughly to obtain a precursor solution.

[0011] The air bubbles in the precursor solution are removed to obtain a de-air-containing precursor solution.

[0012] The initiator and crosslinking agent are added to the degassing precursor solution and stirred until completely dissolved to obtain the prepolymer solution;

[0013] The prepolymer solution is subjected to free radical polymerization under preset conditions to obtain a high-strength, tough, and low-swelling ion-conducting hydrogel.

[0014] As a preferred embodiment of the preparation method described in this invention, the free radical polymerization method includes at least one of temperature-initiated or light-initiated free radical polymerization.

[0015] In a preferred embodiment of the preparation method described in this invention, the concentration of acrylic acid in the precursor solution is 2.5–4 mol / L, the concentration of acrylamide in the precursor solution is 1–2.5 mol / L, the concentration of phytic acid in the precursor solution is 0.2–0.4 mol / L, and the concentration of sodium carboxymethyl cellulose in the precursor solution is 5–18 mg / mL.

[0016] In a preferred embodiment of the preparation method described in this invention, the initiator is 0.05–0.4 mol% of the total molar amount of acrylic acid and acrylamide.

[0017] As a preferred embodiment of the preparation method of the present invention, the initiator includes a free radical polymerization initiator selected from at least one of ammonium persulfate, potassium persulfate and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0018] In a preferred embodiment of the preparation method described in this invention, the crosslinking agent includes a crosslinking agent with double bonds at the end group, selected from at least one of polyethylene glycol diacrylate and N,N'-methylenebisacrylamide.

[0019] In a preferred embodiment of the preparation method described in this invention, the crosslinking agent is 0.05–0.2 mol% of the total molar amount of acrylic acid and acrylamide.

[0020] Another objective of this invention is to overcome the shortcomings of the prior art and provide a high-strength, low-swelling ion-conducting hydrogel, wherein the hydrogel has a tensile elongation at break of 875–1082%, a tensile stress at break of 0.53–2.05 MPa, and a tensile toughness of 2.19–10.57 MJ / m. 3 ;

[0021] When the compression reaches 80% of the strain, the compressive stress is 3.53–8.00 MPa, and the compressive modulus is 352.68–663.28 kPa;

[0022] The hydrogel has a swelling rate of 100%–150% in water;

[0023] The tensile elongation at break of the hydrogel after swelling in water is 612-805%, and the tensile stress at break is 326-613 kPa.

[0024] The swelling rate of hydrogels in artificial sweat is 160–215%;

[0025] The swelling rate of the hydrogel in artificial seawater is 8.0%–20.5%;

[0026] The conductivity of the ion-conducting hydrogel is 1.06–2.39 S / m.

[0027] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of a high-strength, tough, low-swelling ion-conducting hydrogel in a sensor, wherein the sensor includes a flexible sensor.

[0028] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of a high-strength, tough, low-swelling ion-conducting hydrogel in the fabrication of wearable devices.

[0029] Beneficial effects of this invention:

[0030] (1) This invention develops a multifunctional ion-conducting hydrogel through the synergistic enhancement effect of phytic acid and carboxymethyl cellulose. This hydrogel has excellent mechanical properties, achieves low swelling in water and artificial seawater, and also has good conductivity. The preparation method is simple, the operation is controllable, and it is easy to industrialize.

[0031] (2) In the ion-conductive hydrogel provided by the present invention, the poly(acrylic acid-co-acrylamide) molecular chain and the rigid chain of carboxymethyl cellulose form a double network structure, and the phytic acid forms a physical cross-linking structure through hydrogen bonding with the poly(acrylic acid-co-acrylamide) and carboxymethyl cellulose. On the one hand, the strong hydrogen bonding interaction between the phytic acid and the poly(acrylic acid-co-acrylamide) molecular chain induces the stable phase separation of poly(acrylic acid-co-acrylamide), and the rigid chain of carboxymethyl cellulose and the poly(acrylic acid-co-acrylamide) molecular chain form a double network, which further enhances the mechanical properties and fatigue resistance of the hydrogel. On the other hand, the strong hydrogen bonding interaction between the phytic acid and carboxymethyl cellulose can inhibit the attraction of phytic acid to water molecules and the diffusion of phytic acid molecules, thereby reducing the swelling performance of the hydrogel and obtaining a low-swelling hydrogel.

[0032] (3) The ion-conductive hydrogel provided by the present invention exhibits high sensitivity in the tensile strain range of 0-800%. The low swelling in seawater can further broaden the application scenarios of the hydrogel and expand its working range. In addition, the introduction of phytic acid not only endows the hydrogel with excellent conductivity and strain sensing ability, but also endows the hydrogel with significant antifreeze, antibacterial and biocompatibility properties, showing great application potential in multifunctional wearable smart sensors. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0034] Figure 1 This is a schematic diagram illustrating the preparation of the hydrogel in an embodiment of the present invention.

[0035] Figure 2 The tensile property curves are those of the hydrogels in Examples 1 and 4 of this invention.

[0036] Figure 3 The compression performance curves of the hydrogels in Examples 1 and 4 of this invention are shown.

[0037] Figure 4 This is a comparison chart of the swelling properties of the hydrogels in water for Examples 1 and 3 of the present invention.

[0038] Figure 5 The diagram shows the swelling properties of the hydrogel in different solutions of Example 1 of the present invention.

[0039] Figure 6The graphs show the electrical conductivity of the hydrogels in Examples 1 and 4 of this invention.

[0040] Figure 7 The graph shows the relative resistance change (ΔR / R0) and strain coefficient (GF) of the hydrogel in Example 1 of the present invention under tensile strain conditions of 0-800%.

[0041] Figure 8 This is a diagram showing the cyclic conductivity stability of the hydrogel in Example 1 of the present invention at 100% tensile strain.

[0042] Figure 9 This is a diagram showing the mixing results of Comparative Example 5 of the present invention. Detailed Implementation

[0043] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0044] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0045] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0046] The polyethylene glycol diacrylate used in this invention has an average molecular weight of approximately 575 and is a commercially available product; all other raw materials are also commercially available products.

[0047] Performance testing conditions in this embodiment of the invention:

[0048] Mechanical properties: The mechanical testing of the hydrogel was performed using a universal testing machine;

[0049] Hydrogel samples were cut into dumbbell shapes (gauge length 25 mm, width 4 mm, thickness 2 mm) for tensile testing and stretched at a rate of 50 mm / min until the fracture point. Toughness was calculated by the area under the stress-strain curve.

[0050] For the compression test, the hydrogel sample was cut into a cylindrical shape (10 mm in diameter and 5 mm in thickness) and compressed at a rate of 0.5 mm / min until 80% strain. The elastic modulus (E) was calculated from the slope of the fitted line in the linear range of the stress-strain curve.

[0051] Swelling properties: The hydrogel was cut into samples with a diameter of 10 mm and a thickness of 2 mm;

[0052] Immerse each sample in deionized water, artificial sweat, or artificial seawater at room temperature until equilibrium swelling is achieved. Measure the mass of the swollen hydrogel at regular intervals and calculate the swelling ratio using the following equation:

[0053] Swelling ratio = ((W) s -W0) / W0)*100%

[0054] Among them W s W and W0 are the weights of the swollen hydrogel and the original hydrogel, respectively.

[0055] Conductivity: The hydrogel was cut into samples with dimensions of 50mm × 5mm × 2mm;

[0056] The conductivity of the hydrogel was determined using a digital four-probe tester. Tensile loads of varying magnitudes were applied to the hydrogel using a universal testing machine, and the changes in their resistance were recorded using an electrochemical workstation.

[0057] Calculate the change in resistance (ΔR / R0) using the following formula:

[0058]

[0059] Where R0 and R are the resistances when no strain is applied and when strain is applied, respectively.

[0060] The strain coefficient (GF) is calculated using the following formula:

[0061] GF=(ΔR / R0) / ε, where ε is the tensile strain.

[0062] Example 1

[0063] (1) Dissolve acrylic acid (4 mol / L), acrylamide (1 mol / L), phytic acid (0.4 mol / L), and sodium carboxymethyl cellulose (11.1 mg / mL) in deionized water, mix well, and obtain the precursor solution;

[0064] (2) The precursor solution was ultrasonically treated for 10 min to remove air bubbles;

[0065] (3) The initiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (0.3 mol%) and the crosslinking agent polyethylene glycol diacrylate (0.1 mol%) were added to the above solution and stirred until completely dissolved to obtain a prepolymer solution. The prepolymer solution was irradiated under ultraviolet light for 60 min and obtained by free radical polymerization to obtain the ion-conductive hydrogel.

[0066] Hydrogel preparation methods such as Figure 1 As shown.

[0067] According to the universal testing machine test, the elongation at break of the hydrogel in this embodiment is 1082%, the tensile stress at break is 2.05 MPa, and the tensile toughness is 10.57 MJ / m. 3 ,like Figure 2 As shown;

[0068] When the compression reaches 80% of the compressive strain, the compressive stress is 8.00 MPa and the compressive modulus is 663.28 kPa. Figure 3 As shown.

[0069] like Figure 4 As shown, the swelling rate of the hydrogel in water in this embodiment is only 100%, demonstrating a good anti-swelling effect.

[0070] Furthermore, the swelling rate of the hydrogel in this embodiment is approximately 160% in artificial sweat, while the swelling rate in artificial seawater initially increases to 40% and then decreases, ultimately reaching only 8%, demonstrating excellent anti-swelling performance. The initial increase in swelling rate may be due to the high salt ion concentration in the artificial seawater, as shown in the results below. Figure 5 .

[0071] In this embodiment, the hydrogel has a conductivity of 2.39 S / m. (See [reference needed]). Figure 6 ;

[0072] Further experiments revealed that the hydrogel maintained good sensitivity within a tensile strain range of 0–800%, with the strain coefficient GF increasing from 0.95 (≤150%) to 1.84 (150–300%) and 2.23 (≥300%), exhibiting a wide sensing range. (See...) Figure 7 .

[0073] Meanwhile, applying 200 tensile loading and unloading cycles of 100% strain to the hydrogel revealed that it maintained a continuous and stable resistance signal during the test, demonstrating excellent strain-sensing fatigue resistance. Figure 8 .

[0074] Example 2

[0075] (1) Dissolve acrylic acid (3.8 mol / L), acrylamide (1.2 mol / L), phytic acid (0.38 mol / L), and sodium carboxymethyl cellulose (18.0 mg / mL) in deionized water, mix well, and obtain a precursor solution;

[0076] (2) The precursor solution was ultrasonically treated for 15 min to remove air bubbles;

[0077] (3) Add the initiator ammonium persulfate (0.4 mol%) and the crosslinking agent N,N'-methylenebisacrylamide (0.1 mol%) to the above solution and stir until completely dissolved to obtain a prepolymer solution. The prepolymer solution is then subjected to free radical polymerization in a water bath at 60°C for 24 hours to obtain the ion-conductive hydrogel.

[0078] In this embodiment, the hydrogel has an elongation at break of 945%, a tensile stress at break of 1.83 MPa, and a tensile toughness of 9.27 MJ / m. 3 ;

[0079] When compressed to 80% of the compressive strain, the compressive stress is 7.53 MPa and the compressive modulus is 603.16 kPa; the swelling rate in water is 112%, the swelling rate in artificial sweat is 178%, and the swelling rate in artificial seawater is 9.5%; the conductivity is 2.14 S / m.

[0080] Example 3

[0081] (1) Dissolve acrylic acid (3.5 mol / L), acrylamide (1.5 mol / L), phytic acid (0.35 mol / L), and sodium carboxymethyl cellulose (15.3 mg / mL) in deionized water, mix well, and obtain a precursor solution;

[0082] (2) The precursor solution was ultrasonically treated for 15 min to remove air bubbles;

[0083] (3) The initiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (0.35 mol%) and the crosslinking agent polyethylene glycol diacrylate (0.05 mol%) were added to the above solution and stirred until completely dissolved to obtain a prepolymer solution. The prepolymer solution was irradiated under ultraviolet light for 30 min and obtained by free radical polymerization to obtain the ion-conductive hydrogel.

[0084] In this embodiment, the hydrogel has an elongation at break of 921%, a tensile stress at break of 1.48 MPa, and a tensile toughness of 7.83 MJ / m. 3 When the compression reaches 80% of the compressive strain, the compressive stress is 7.06 MPa and the compressive modulus is 564.19 kPa.

[0085] Its swelling rate in water is 129%, in artificial sweat it is 184%, and in artificial seawater it is 11.3%; its conductivity is 2.01 S / m.

[0086] Example 4

[0087] (1) Dissolve acrylic acid (3.3 mol / L), acrylamide (1.7 mol / L), phytic acid (0.3 mol / L), and sodium carboxymethyl cellulose (12.4 mg / mL) in deionized water, mix well, and obtain a precursor solution;

[0088] (2) The precursor solution was ultrasonically treated for 20 min to remove air bubbles;

[0089] (3) The initiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (0.25 mol%) and the crosslinking agent polyethylene glycol diacrylate (0.15 mol%) were added to the above solution and stirred until completely dissolved to obtain a prepolymer solution. The prepolymer solution was irradiated under ultraviolet light for 30 min and obtained by free radical polymerization to obtain the ion-conductive hydrogel.

[0090] In this embodiment, the hydrogel has an elongation at break of 912%, a tensile stress of 1.03 MPa, and a toughness of 5.87 MJ / m3 under tension; when compressed to 80% of the compressive strain, the compressive stress is 6.28 MPa and the compressive modulus is 519.23 kPa.

[0091] Its swelling rate in water is 134%, in artificial sweat it is 191%, in artificial seawater it is 13.8%, and its conductivity is 1.82 S / m.

[0092] Example 5

[0093] (1) Dissolve acrylic acid (3 mol / L), acrylamide (2 mol / L), phytic acid (0.25 mol / L), and sodium carboxymethyl cellulose (10.1 mg / mL) in deionized water, mix well, and obtain a precursor solution;

[0094] (2) The precursor solution was ultrasonically treated for 25 min to remove air bubbles;

[0095] (3) Potassium persulfate (0.2 mol%) as initiator and N,N'-methylenebisacrylamide (0.15 mol%) as crosslinking agent are added to the above solution and stirred until completely dissolved to obtain a prepolymer solution. The prepolymer solution is then subjected to free radical polymerization in a water bath at 50°C for 48 hours to obtain the ion-conductive hydrogel.

[0096] In this embodiment, the hydrogel has an elongation at break of 890%, a tensile stress at break of 0.86 MPa, and a tensile toughness of 4.92 MJ / m. 3 ;

[0097] When compressed to 80% of the compressive strain, the compressive stress is 5.72 MPa and the compressive modulus is 467.24 kPa; the swelling rate in water is 139%, the swelling rate in artificial sweat is 203%, and the swelling rate in artificial seawater is 14.6%; the conductivity is 1.66 S / m.

[0098] Example 6

[0099] (1) Dissolve acrylic acid (2.8 mol / L), acrylamide (2.2 mol / L), phytic acid (0.22 mol / L), and sodium carboxymethyl cellulose (7.4 mg / mL) in deionized water, mix well, and obtain the precursor solution;

[0100] (2) The precursor solution was ultrasonically treated for 25 min to remove air bubbles;

[0101] (3) Potassium persulfate (0.1 mol%) as an initiator and N,N'-methylenebisacrylamide (0.2 mol%) as a crosslinking agent are added to the above solution and stirred until completely dissolved to obtain a prepolymer solution. The prepolymer solution is then subjected to free radical polymerization in a water bath at 40°C for 72 hours to obtain the ion-conductive hydrogel.

[0102] In this embodiment, the hydrogel has an elongation at break of 882%, a tensile stress at break of 0.79 MPa, and a tensile toughness of 3.84 MJ / m. 3 When compressed to 80% of the compressive strain, the compressive stress is 4.14 MPa and the compressive modulus is 403.19 kPa; the swelling rate in water is 142%, the swelling rate in artificial sweat is 207%, and the swelling rate in artificial seawater is 18.2%; the conductivity is 1.43 S / m.

[0103] Example 7

[0104] (1) Dissolve acrylic acid (2.5 mol / L), acrylamide (2.5 mol / L), phytic acid (0.2 mol / L), and sodium carboxymethyl cellulose (5.0 mg / mL) in deionized water, mix well, and obtain a precursor solution;

[0105] (2) The precursor solution was ultrasonically treated for 30 minutes to remove air bubbles;

[0106] (3) The initiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (0.05 mol%) and the crosslinking agent polyethylene glycol diacrylate (0.2 mol%) were added to the above solution and stirred until completely dissolved to obtain a prepolymer solution. The prepolymer solution was irradiated under ultraviolet light for 90 min and obtained by free radical polymerization to obtain the ion-conductive hydrogel.

[0107] In this embodiment, the hydrogel has an elongation at break of 875%, a tensile stress at break of 0.53 MPa, and a tensile toughness of 2.19 MJ / m. 3 ;

[0108] When compressed to 80% of the compressive strain, the compressive stress is 3.53 MPa and the compressive modulus is 352.68 kPa; the swelling rate in water is 150%, the swelling rate in artificial sweat is 210%, and the swelling rate in artificial seawater is 20.5%; the conductivity is 1.06 S / m.

[0109] Comparative Example 1

[0110] Without adding phytic acid and sodium carboxymethyl cellulose, in Example 1: acrylic acid (4 mol / L) and acrylamide (1 mol / L) were dissolved in deionized water and mixed thoroughly to obtain the precursor solution;

[0111] Other conditions are the same as in Example 1; its tensile properties, compressive properties, swelling properties, and electrical conductivity are respectively shown in [reference needed]. Figure 2 , 3 4 and 6.

[0112] The hydrogel exhibits an elongation at break of 829%, a tensile stress of 312.98 kPa, and a tensile toughness of 1.45 MJ / m. 3 When compressed to 80% of the compressive strain, the compressive stress is 3.01 MPa and the compressive modulus is 427.66 kPa; the swelling rate in water is 200%; and the conductivity is 0.13 S / m.

[0113] As can be seen, compared with Example 1, the strength and toughness of the hydrogel in Comparative Example 1 are significantly reduced, the anti-swelling effect is poor, and the conductivity is weak.

[0114] Comparative Example 2

[0115] Without phytic acid, in Example 1: acrylic acid (4 mol / L), acrylamide (1 mol / L), and sodium carboxymethyl cellulose (11.1 mg / mL) were dissolved in deionized water and mixed thoroughly to obtain the precursor solution; other conditions were the same as in Example 1. Its tensile properties, compressive properties, swelling properties, and electrical conductivity are shown below. Figure 2 , 3 4 and 6.

[0116] The hydrogel has an elongation at break of 695%, a tensile stress at break of 323.56 kPa, and a tensile toughness of 1.42 MJ / m. 3 When compressed to 80% of the compressive strain, the compressive stress is 4.00 MPa and the compressive modulus is 580.21 kPa; the swelling rate in water is 446%; and the conductivity is 0.09 S / m.

[0117] As can be seen, compared with Example 1, the strength and toughness of the hydrogel in Comparative Example 2 are significantly reduced, the anti-swelling effect is poor, and the conductivity is weak.

[0118] Comparative Example 3

[0119] Without adding sodium carboxymethyl cellulose, in Example 1: acrylic acid (4 mol / L), acrylamide (1 mol / L), and phytic acid (0.4 mol / L) were dissolved in deionized water and mixed thoroughly to obtain a precursor solution.

[0120] Other conditions are the same as in Example 1;

[0121] Its tensile properties, compressive properties, swelling properties, and electrical conductivity are respectively shown in the table below. Figure 2 , 3 4 and 6.

[0122] The hydrogel has an elongation at break of 1178%, a tensile stress at break of 1.09 MPa, and a tensile toughness of 5.95 MJ / m. 3 When compressed to 80% of the compressive strain, the compressive stress is 5.98 MPa, and the compressive modulus is 606.33 kPa; the swelling rate in water is 496%; and the conductivity is 2.51 S / m. It can be seen that, compared with Example 1, the hydrogel of Comparative Example 3 has comparable conductivity, but its strength and toughness are reduced, and its anti-swelling effect is poor.

[0123] Comparative Example 4

[0124] Based on Example 1, sodium carboxymethyl cellulose was not added. Instead, the amount of sodium carboxymethyl cellulose added was converted into phytic acid, and the calculated concentration of phytic acid was 0.42 mol / L, as detailed below:

[0125] Acrylic acid (4 mol / L), acrylamide (1 mol / L), and phytic acid (0.42 mol / L) were dissolved in deionized water and mixed thoroughly to obtain the precursor solution.

[0126] Other conditions are the same as in Example 1. Its tensile properties, compressive properties, swelling properties, and electrical conductivity are shown in the figures below. Figure 2 , 3 And 6.

[0127] The hydrogel has an elongation at break of 1118%, a tensile stress at break of 1.25 MPa, and a tensile toughness of 7.28 MJ / m. 3 When compressed to 80% of the compressive strain, the compressive stress is 6.67 MPa, and the compressive modulus is 615.35 kPa; the swelling rate in water is 538%; and the conductivity is 2.63 S / m. It can be seen that, compared with Example 1, the hydrogel of Comparative Example 4 has comparable conductivity, but its strength and toughness are reduced, and its anti-swelling effect is poor.

[0128] Comparative Example 5

[0129] Based on Example 1, phytic acid was omitted, and the amount of phytic acid added was converted to sodium carboxymethyl cellulose. The calculated concentration of carboxymethyl cellulose was 275.1 mg / mL. Acrylic acid (4 mol / L), acrylamide (1 mol / L), and sodium carboxymethyl cellulose (275.1 mg / mL) were dissolved in deionized water. It was found that they could not be completely dissolved, preventing further experiments. See details below. Figure 9 .

[0130] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. A method for preparing a high-strength, tough, low-swelling ion-conducting hydrogel, characterized in that: include, Acrylic acid, acrylamide, phytic acid, and sodium carboxymethyl cellulose were dissolved in deionized water and mixed thoroughly to obtain a precursor solution. The concentration of acrylic acid in the precursor solution was 2.5-4 mol / L, the concentration of acrylamide in the precursor solution was 1-2.5 mol / L, the concentration of phytic acid in the precursor solution was 0.2-0.4 mol / L, the concentration of sodium carboxymethyl cellulose in the precursor solution was 5.0-18.0 mg / mL, and the total concentration of acrylic acid and acrylamide in the precursor solution was 5 mol / L. The air bubbles in the precursor solution are removed to obtain a de-air-containing precursor solution. The initiator and crosslinking agent are added to the degassed precursor solution and stirred until completely dissolved to obtain a prepolymer solution. The crosslinking agent includes a crosslinking agent with double bonds at the end groups, selected from at least one of polyethylene glycol diacrylate and N,N'-methylenebisacrylamide. The crosslinking agent is 0.05~0.2 mol% of the total molar amount of acrylic acid and acrylamide. The prepolymer solution is subjected to free radical polymerization under preset conditions to obtain a high-strength, tough, and low-swelling ion-conducting hydrogel.

2. The preparation method according to claim 1, characterized in that: Free radical polymerization methods include at least one of temperature-initiated or light-initiated free radical polymerization.

3. The preparation method according to claim 1, characterized in that: The initiator is 0.05 to 0.4 mol of the total molar amount of acrylic acid and acrylamide.

4. The preparation method according to claim 3, characterized in that: The initiator includes a free radical polymerization initiator selected from at least one of ammonium persulfate, potassium persulfate, and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

5. The high-strength, tough, and low-swelling ion-conducting hydrogel prepared by any one of claims 1 to 4 is characterized in that: The hydrogel exhibits a tensile elongation at break of 875–1082%, a tensile stress at break of 0.53–2.05 MPa, and a tensile toughness of 2.19–10.57 MJ / m. 3 ; When the compression reaches 80% of the strain, the compressive stress is 3.53~8.00 MPa, and the compressive modulus is 352.68~663.28 kPa; The swelling rate of the hydrogel in water is 100%~150%; The tensile elongation at break of the hydrogel after swelling in water is 612-805%, and the tensile stress at break is 326-613 kPa. The swelling rate of hydrogels in artificial sweat is 160-215%; The swelling rate of the hydrogel in artificial seawater is 8.0%~20.5%; The conductivity of the ion-conducting hydrogel is 1.06~2.39 S / m.

6. The application of the high-strength, tough, low-swelling ion-conducting hydrogel of claim 5 in a sensor, characterized in that: The sensor includes a flexible sensor.

7. The application of the high-strength, tough, low-swelling ion-conducting hydrogel of claim 5 in the preparation of wearable devices.

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